Horacio Dottori - Academia.edu (original) (raw)
Papers by Horacio Dottori
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We have analyzed the frequency and properties of the nuclear activity in a sample of galaxies wit... more We have analyzed the frequency and properties of the nuclear activity in a sample of galaxies with circumnuclear rings and spirals (CNRs). This sample was compared with a control sample of galaxies with very similar global properties but without circumnuclear rings. We discuss the relevance of the results in regard to the AGN feeding processes and present the following results:
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Revista mexicana de astronomía y astrofísica
ABSTRACT
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Revista mexicana de astronomía y astrofísica
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We discuss the morphology, kinematics, and physical conditions of the emitting gas of the interac... more We discuss the morphology, kinematics, and physical conditions of the emitting gas of the interacting system IRAS 20048-6621. We present as well numerical simulations of this interacting system, discovered by David Mc Leish in 1946. The main galaxy (McL A) is an edge-on giant spiral galaxy with highly distorted NW side. On this side is also located McL B, the
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Proceedings of the International Astronomical Union, 2004
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We study the spiral pattern in the inner 6.5 arcsec (1arcsec ≅265pc) of the Seyfert 2 nucleus of ... more We study the spiral pattern in the inner 6.5 arcsec (1arcsec ≅265pc) of the Seyfert 2 nucleus of NGC1241. GEMINI-N K and J bands, as well as HST Paalpha and (V+R) ones are analysed through 2-D and 1-D Fourier techniques. A small (≅ 500 pc) long bar surrouded by a r = 700pc ring, both emitting in Paalpha are found.
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Proceedings of the International Astronomical Union, 2004
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Astronomy and Astrophysics Supplement Series, 1998
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ABSTRACT We study the spiral arms structure for eight discoidal galaxies with different Elmegreen... more ABSTRACT We study the spiral arms structure for eight discoidal galaxies with different Elmegreen & Elmegreen class (E&E). The galaxies are NGC514, NGC753, NGC1058, NGC1232, NGC1300, NGC1365, NGC1566 and NGC1637. We analize by means of Fast Fourier Transform CCD images in B or G and I colors, with the aim of describing the perturbation that originates the spiral arms and the stellar formation associated to them. The method, matematically based upon a superposition of one to six armed logarithmic spirals, reveals that: In spite of the two armed components predominance in the Gran Design galaxies (E&E class 12) NGC1300, NGC1365 and NGC1566, assimetric components are needed to describe the whole arm structure. The two arms patern is trailing. The two galaxies with fragmented arms NGC1058 (E&E class 3) and NGC1637 (E&E class 5) show many relevants components, while in the multiple arms galaxies NGC1232, NGC753 and NGC514 (E&E class 9) at least one of the assymetric components is as important as the two armed one. Our method allows also to determine the corrotation resonance (CR). Surprisingly many of the analized galaxies present more than one CR, even among the Grand Design ones, indicating that spiral patterns have not a constant velocity or that different spiral patterns couple to produce the observed arms structure. The two galaxies with fragmented arms show many relevant Fourier components, with many peaks in each of them. Interestingly, the character of the main bissymmetrics component is leading in both cases. This type of analysis will allow to draw a disk potential perturbation to study orbits behavior.
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Astronomy & Astrophysics, 2002
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The Astronomical Journal, 2021
We observed the compact group of galaxies NGC 6845 with GMOS-S imaging and long-slit spectroscopy... more We observed the compact group of galaxies NGC 6845 with GMOS-S imaging and long-slit spectroscopy. The group itself is comprised of two spiral galaxies and two S0 galaxies, and shows signs of gravitational interaction among them. While the spiral galaxies have been already well studied, the two S0 galaxies have received little attention. We investigate the morphology and stellar kinematics of the two S0 galaxies in detail in order to derive the value for their mass and subsequently incorporate them into the mass model for the group. It was found that the internal kinematics of the largest S0 (NGC 6845 C) is mostly regular, while the smallest S0 (NGC 6845 D) shows some hint of interaction, most likely with NGC 6845 C and NGC 6845 A. The new determination of the dynamical mass of the group implies that the group mass has to be 10 times the combined mass of the individual members according to their internal kinematics. The results point to an early stage of the group interaction and also to the possibility that it has still not reached virial equilibrium. From the galaxy evolution viewpoint, this group represents an example of the case of the transformation of Spirals into S0 galaxies in dense environments.
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The Astronomical Journal, 2021
We observed the compact group of galaxies NGC 6845 with GMOS-S imaging and long-slit spectroscopy... more We observed the compact group of galaxies NGC 6845 with GMOS-S imaging and long-slit spectroscopy. The group itself is comprised of two spiral galaxies and two S0 galaxies, and shows signs of gravitational interaction among them. While the spiral galaxies have been already well studied, the two S0 galaxies have received little attention. We investigate the morphology and stellar kinematics of the two S0 galaxies in detail in order to derive the value for their mass and subsequently incorporate them into the mass model for the group. It was found that the internal kinematics of the largest S0 (NGC 6845 C) is mostly regular, while the smallest S0 (NGC 6845 D) shows some hint of interaction, most likely with NGC 6845 C and NGC 6845 A. The new determination of the dynamical mass of the group implies that the group mass has to be 10 times the combined mass of the individual members according to their internal kinematics. The results point to an early stage of the group interaction and also to the possibility that it has still not reached virial equilibrium. From the galaxy evolution viewpoint, this group represents an example of the case of the transformation of Spirals into S0 galaxies in dense environments.
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Proceedings of the International Astronomical Union, 2015
A population of young, massive stellar cluster complexes with near-infrared (NIR) colors indicati... more A population of young, massive stellar cluster complexes with near-infrared (NIR) colors indicating high extinction (i.e. Av ~ 7m) was identified on HAWK-I/VLT images of several nearby, grand-design spiral galaxies. Models suggest that they are very young cluster complexes still embedded in a dust/gas envelope which will be expelled after 5-7 Myr. This type of very young, embedded clusters are not seen in optical studies using HST data. A detailed comparison of HST and HAWK-I images was done to better understand the discrepancy between the optical and NIR detection of stellar clusters in nearby galaxies. More than 70% of the NIR clusters are located close to dust lanes which would make an optical detection difficult. A comparison of the ALMA CO(1-0)-map of NGC 4321 and the young, massive clusters shows that 60% of them have CO emission within 2“ indicating a correlation between giant molecular clouds and formation of massive clusters.
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We report the discovery of three proplyd-like structures in the giant HII region NGC 3603. The em... more We report the discovery of three proplyd-like structures in the giant HII region NGC 3603. The emission nebulae are clearly resolved in narrow-band and broad-band HST/WFPC2 observations in the optical and broad-band VLT/ISAAC observations in the near-infrared. All three nebulae are tadpole shaped, with the bright ionization front at the head facing the central cluster and a fainter ionization front around the tail pointing away from the cluster. Typical sizes are 6,000 A.U. × 20,000 A.U. The nebulae share the overall morphology of the proplyds (“PROto PLanetarY DiskS”) in Orion, but are 20 to 30 times larger in size. Additional faint filaments located between the nebulae and the central ionizing cluster can be interpreted as bow shocks resulting from the interaction of the fast winds from
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The Sy 2 galaxy NGC 1241 presents a 1.5 kpc large circumnuclear ring of star formation (CNR) embr... more The Sy 2 galaxy NGC 1241 presents a 1.5 kpc large circumnuclear ring of star formation (CNR) embracing a small bar plus leading arms. Those structures are P alpha emitters, but barely seen in H alpha. It presents also stellar trailing arms inside the CNR. GEMINI and HST imagery allow the construction of high resolution (V-H) and (J-K_s) color maps as well as a (J-K_s) vs. K color-magnitude diagram (CMD) of this complex region. The CNR is heavily obscured in V, but a fairly transparent window appears in the direction of the nucleus. Nonetheless, the nucleus presents a (J-K_s) color that is redder than the CNR. The CNR is composed of extremely young HII regions still enshrouded in their dust cocoons. However, the nuclear (J-K_s) color can not be explained in this manner. Therefore, we propose the contribution of C-Stars as the most feasible mechanism for explaining the colors. If the nuclear stellar population is comparable to that of the LMC bar, 500 C-stars and 25000 AGB O-rich star...
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Bookmarks Related papers MentionsView impact
We have analyzed the frequency and properties of the nuclear activity in a sample of galaxies wit... more We have analyzed the frequency and properties of the nuclear activity in a sample of galaxies with circumnuclear rings and spirals (CNRs). This sample was compared with a control sample of galaxies with very similar global properties but without circumnuclear rings. We discuss the relevance of the results in regard to the AGN feeding processes and present the following results:
Bookmarks Related papers MentionsView impact
Bookmarks Related papers MentionsView impact
Revista mexicana de astronomía y astrofísica
ABSTRACT
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Revista mexicana de astronomía y astrofísica
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We discuss the morphology, kinematics, and physical conditions of the emitting gas of the interac... more We discuss the morphology, kinematics, and physical conditions of the emitting gas of the interacting system IRAS 20048-6621. We present as well numerical simulations of this interacting system, discovered by David Mc Leish in 1946. The main galaxy (McL A) is an edge-on giant spiral galaxy with highly distorted NW side. On this side is also located McL B, the
Bookmarks Related papers MentionsView impact
Proceedings of the International Astronomical Union, 2004
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We study the spiral pattern in the inner 6.5 arcsec (1arcsec ≅265pc) of the Seyfert 2 nucleus of ... more We study the spiral pattern in the inner 6.5 arcsec (1arcsec ≅265pc) of the Seyfert 2 nucleus of NGC1241. GEMINI-N K and J bands, as well as HST Paalpha and (V+R) ones are analysed through 2-D and 1-D Fourier techniques. A small (≅ 500 pc) long bar surrouded by a r = 700pc ring, both emitting in Paalpha are found.
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Proceedings of the International Astronomical Union, 2004
Bookmarks Related papers MentionsView impact
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Astronomy and Astrophysics Supplement Series, 1998
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ABSTRACT We study the spiral arms structure for eight discoidal galaxies with different Elmegreen... more ABSTRACT We study the spiral arms structure for eight discoidal galaxies with different Elmegreen & Elmegreen class (E&E). The galaxies are NGC514, NGC753, NGC1058, NGC1232, NGC1300, NGC1365, NGC1566 and NGC1637. We analize by means of Fast Fourier Transform CCD images in B or G and I colors, with the aim of describing the perturbation that originates the spiral arms and the stellar formation associated to them. The method, matematically based upon a superposition of one to six armed logarithmic spirals, reveals that: In spite of the two armed components predominance in the Gran Design galaxies (E&E class 12) NGC1300, NGC1365 and NGC1566, assimetric components are needed to describe the whole arm structure. The two arms patern is trailing. The two galaxies with fragmented arms NGC1058 (E&E class 3) and NGC1637 (E&E class 5) show many relevants components, while in the multiple arms galaxies NGC1232, NGC753 and NGC514 (E&E class 9) at least one of the assymetric components is as important as the two armed one. Our method allows also to determine the corrotation resonance (CR). Surprisingly many of the analized galaxies present more than one CR, even among the Grand Design ones, indicating that spiral patterns have not a constant velocity or that different spiral patterns couple to produce the observed arms structure. The two galaxies with fragmented arms show many relevant Fourier components, with many peaks in each of them. Interestingly, the character of the main bissymmetrics component is leading in both cases. This type of analysis will allow to draw a disk potential perturbation to study orbits behavior.
Bookmarks Related papers MentionsView impact
Astronomy & Astrophysics, 2002
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The Astronomical Journal, 2021
We observed the compact group of galaxies NGC 6845 with GMOS-S imaging and long-slit spectroscopy... more We observed the compact group of galaxies NGC 6845 with GMOS-S imaging and long-slit spectroscopy. The group itself is comprised of two spiral galaxies and two S0 galaxies, and shows signs of gravitational interaction among them. While the spiral galaxies have been already well studied, the two S0 galaxies have received little attention. We investigate the morphology and stellar kinematics of the two S0 galaxies in detail in order to derive the value for their mass and subsequently incorporate them into the mass model for the group. It was found that the internal kinematics of the largest S0 (NGC 6845 C) is mostly regular, while the smallest S0 (NGC 6845 D) shows some hint of interaction, most likely with NGC 6845 C and NGC 6845 A. The new determination of the dynamical mass of the group implies that the group mass has to be 10 times the combined mass of the individual members according to their internal kinematics. The results point to an early stage of the group interaction and also to the possibility that it has still not reached virial equilibrium. From the galaxy evolution viewpoint, this group represents an example of the case of the transformation of Spirals into S0 galaxies in dense environments.
Bookmarks Related papers MentionsView impact
The Astronomical Journal, 2021
We observed the compact group of galaxies NGC 6845 with GMOS-S imaging and long-slit spectroscopy... more We observed the compact group of galaxies NGC 6845 with GMOS-S imaging and long-slit spectroscopy. The group itself is comprised of two spiral galaxies and two S0 galaxies, and shows signs of gravitational interaction among them. While the spiral galaxies have been already well studied, the two S0 galaxies have received little attention. We investigate the morphology and stellar kinematics of the two S0 galaxies in detail in order to derive the value for their mass and subsequently incorporate them into the mass model for the group. It was found that the internal kinematics of the largest S0 (NGC 6845 C) is mostly regular, while the smallest S0 (NGC 6845 D) shows some hint of interaction, most likely with NGC 6845 C and NGC 6845 A. The new determination of the dynamical mass of the group implies that the group mass has to be 10 times the combined mass of the individual members according to their internal kinematics. The results point to an early stage of the group interaction and also to the possibility that it has still not reached virial equilibrium. From the galaxy evolution viewpoint, this group represents an example of the case of the transformation of Spirals into S0 galaxies in dense environments.
Bookmarks Related papers MentionsView impact
Proceedings of the International Astronomical Union, 2015
A population of young, massive stellar cluster complexes with near-infrared (NIR) colors indicati... more A population of young, massive stellar cluster complexes with near-infrared (NIR) colors indicating high extinction (i.e. Av ~ 7m) was identified on HAWK-I/VLT images of several nearby, grand-design spiral galaxies. Models suggest that they are very young cluster complexes still embedded in a dust/gas envelope which will be expelled after 5-7 Myr. This type of very young, embedded clusters are not seen in optical studies using HST data. A detailed comparison of HST and HAWK-I images was done to better understand the discrepancy between the optical and NIR detection of stellar clusters in nearby galaxies. More than 70% of the NIR clusters are located close to dust lanes which would make an optical detection difficult. A comparison of the ALMA CO(1-0)-map of NGC 4321 and the young, massive clusters shows that 60% of them have CO emission within 2“ indicating a correlation between giant molecular clouds and formation of massive clusters.
Bookmarks Related papers MentionsView impact
Bookmarks Related papers MentionsView impact
Bookmarks Related papers MentionsView impact
We report the discovery of three proplyd-like structures in the giant HII region NGC 3603. The em... more We report the discovery of three proplyd-like structures in the giant HII region NGC 3603. The emission nebulae are clearly resolved in narrow-band and broad-band HST/WFPC2 observations in the optical and broad-band VLT/ISAAC observations in the near-infrared. All three nebulae are tadpole shaped, with the bright ionization front at the head facing the central cluster and a fainter ionization front around the tail pointing away from the cluster. Typical sizes are 6,000 A.U. × 20,000 A.U. The nebulae share the overall morphology of the proplyds (“PROto PLanetarY DiskS”) in Orion, but are 20 to 30 times larger in size. Additional faint filaments located between the nebulae and the central ionizing cluster can be interpreted as bow shocks resulting from the interaction of the fast winds from
Bookmarks Related papers MentionsView impact
The Sy 2 galaxy NGC 1241 presents a 1.5 kpc large circumnuclear ring of star formation (CNR) embr... more The Sy 2 galaxy NGC 1241 presents a 1.5 kpc large circumnuclear ring of star formation (CNR) embracing a small bar plus leading arms. Those structures are P alpha emitters, but barely seen in H alpha. It presents also stellar trailing arms inside the CNR. GEMINI and HST imagery allow the construction of high resolution (V-H) and (J-K_s) color maps as well as a (J-K_s) vs. K color-magnitude diagram (CMD) of this complex region. The CNR is heavily obscured in V, but a fairly transparent window appears in the direction of the nucleus. Nonetheless, the nucleus presents a (J-K_s) color that is redder than the CNR. The CNR is composed of extremely young HII regions still enshrouded in their dust cocoons. However, the nuclear (J-K_s) color can not be explained in this manner. Therefore, we propose the contribution of C-Stars as the most feasible mechanism for explaining the colors. If the nuclear stellar population is comparable to that of the LMC bar, 500 C-stars and 25000 AGB O-rich star...
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